Electronic defrost timer for mechanical refregerator

ABSTRACT

An electronic defrost timer for a mechanical refrigerator is disclosed, which includes an input unit applying its power to the defrost timer and receiving an input of time for controlling the defrost timer, a control unit controlling a compression mode or a defrost mode by using the input time and a program, and an output unit directly controlling the compression mode or the defrost mode under the control of the control unit. According to the electronic defrost timer, since the input unit, the control unit, and the output unit are mounted on a PCB and the compression mode or the defrost mode is controlled by the program, the compression/defrost operation time of the refrigerator can be promptly controlled by a simple modification of the program, without any modification of moldings, and thus the manufacturing cost and time can be saved.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority from Korean Patent Application No. 10-2005-0118284, filed on Dec. 6, 2005 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic defrost timer for a mechanical refrigerator. More particularly, the present invention relates to an electronic defrost timer for a mechanical refrigerator which is provided with an input unit, a control unit, and an output unit mounted on a printed circuit board (PCB), on the same wiring and mounting conditions as those of the existing mechanical defrost timer, and controls a compression mode and a defrost mode by means of a program, so that the compression/defrost operation time of the refrigerator can promptly be controlled by simply changing the program, without any modification of moldings.

2. Description of the Prior Art

Generally, a refrigerator is provided with a defrost timer that defrosts an evaporator on which frost accumulates due to the temperature change in the refrigerator, which occurs during the operation of the refrigerator, by operating a defrost heater at predetermined intervals.

FIG. 1 is a schematic view illustrating the construction of a defrost timer used in a conventional mechanical refrigerator. As shown in FIG. 1, the conventional mechanical refrigerator includes a temperature adjuster (e.g., thermostat) 20 controlling the temperature of the refrigerator, a compressor 50, a defrost heater 40, a mechanical defrost timer 10 switching a power supply to the compressor 50 or the defrost heater 40 by counting the operation time of the compressor or the defrost heater, and a defrost temperature switch 30 detecting the temperature of the defrost heater 40 during the operation of the defrost heater 40.

According to the conventional mechanical defrost timer for the mechanical refrigerator as described above, however, many moldings such as gears, a gear shaft, and so forth, should be changed in order to change the operation time of the mechanical defrost timer, and it is very difficult to accurately control the compression/defrost operation time. Accordingly, it is difficult to immediately cope with the user's request for diverse operation times, and it takes a lot of time in testing the moldings, thereby greatly requiring the manpower, resources, and management cost.

In addition, since there is an increasing possibility that the refrigerant used in the refrigerator will be changed to an explosive refrigerant due to the atmospheric environmental restriction which becomes more tightened in the world (e.g., ozone depletion) and the existing electric contacts are exposed in the air, it may be exploded to cause material and human damages, and due to the reduction of the rotating speed of engaged gears, frictional noises may occur among the gears.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide an electronic defrost timer for a mechanical refrigerator that is provided with an input unit, a control unit, and an output unit mounted on a printed circuit board (PCB), and controls a compression mode and a defrost mode by means of a program.

Another object of the present invention is to provide an electronic defrost timer for a mechanical refrigerator that stores an accumulated time for controlling a compression mode or a defrost mode so as to prevent the accumulated time from being erased even if power supply to the defrost timer is cut off, and re-operates in the compression mode or the defrost mode in accordance with the stored accumulated time.

Still another object of the preset invention is to provide an electronic defrost timer for a mechanical refrigerator that has a structure operating on the same wiring and mounting conditions as those of the existing mechanical defrost timer.

In order to accomplish these objects, there is provided an electronic defrost timer for a mechanical refrigerator, according to the present invention, which includes an input unit applying its power to the defrost timer and receiving an input of time for controlling the defrost timer, a control unit controlling a compression mode or a defrost mode by using the input time and a program, and an output unit directly controlling the compression mode or the defrost mode under the control of the control unit.

In another aspect of the present invention, there is provided an electronic defrost timer for a mechanical refrigerator, which includes an input unit receiving an input of time for controlling the defrost timer, a control unit controlling a compression mode and a defrost mode by using the input time and a program, and an output unit directly controlling the compression mode or the defrost mode under the control of the control unit.

The control unit may include a memory (e.g., RAM) automatically storing the accumulated time to operate in the compression mode or the defrost mode during the operation of the mechanical refrigerator or when the power is cut off.

The memory (e.g., RAM) may be a general memory that automatically stores the accumulated time by using a battery or capacitor provided therein when the power is cut off, or may be a memory (e.g., NVRAM, EEPROM, and so forth) that automatically stores the accumulated time without any power supply from the battery or capacitor provided therein.

The compression mode means a general process in which the compressor of the mechanical refrigerator operates, and the defrost mode means a general process in which the defrost heater of the mechanical refrigerator operates and then give pause to its operation in order to defrost the refrigerator.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view illustrating the construction of a defrost timer used in a conventional mechanical refrigerator;

FIG. 2 is a schematic view illustrating the whole construction of an electronic defrost timer used in a mechanical refrigerator according to the present invention;

FIG. 3 is a block diagram illustrating the construction of an electronic defrost timer for a mechanical refrigerator according to an embodiment of the present invention;

FIG. 4 is a block diagram illustrating the construction of program modules installed in the electronic defrost timer for a mechanical refrigerator according to the present invention;

FIG. 5 is a flowchart explaining the operation principle of the electronic defrost timer for a mechanical refrigerator according to the present invention; and

FIG. 6 is a flowchart explaining a timer routine for checking the system of the electronic defrost timer for a mechanical refrigerator according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The matters defined in the description, such as the detailed construction and elements, are nothing but specific details provided to assist those of ordinary skill in the art in a comprehensive understanding of the invention, and thus the present invention is not limited thereto.

FIG. 2 is a schematic view illustrating the whole construction of an electronic defrost timer used in a mechanical refrigerator according to the present invention, and FIG. 3 is a block diagram illustrating the construction of an electronic defrost timer for a mechanical refrigerator according to an embodiment of the present invention.

Referring to FIGS. 2 and 3, the construction and operation of the electronic defrost timer for a mechanical refrigerator will now be described in detail.

The electronic defrost timer 100 for a mechanical refrigerator according to the present invention, as shown in FIG. 2, is provided with an input unit, a control unit, and an output unit mounted on a printed circuit board (PCB), on the same wiring and mounting conditions as those of the existing mechanical defrost timer as shown in FIG. 1, and controls a compression mode and a defrost mode by means of a program.

The electronic defrost timer 100 includes a control unit 110, an input unit 120, and an output unit 130.

The control unit 110 may be a microcomputer for controlling the whole function of the electronic defrost timer 100, and controls time for controlling a compression mode or a defrost mode of the mechanical refrigerator, i.e., a compression/defrost operation period and a defrost pause time, which have been inputted through the execution of a built-in program. In other words, the control unit 110 alternately controls the compression mode and the defrost mode by up/down-counting the compression/defrost operation period and the defrost pause time.

The program is executed in such a manner that if a predetermined time (e.g., one to three hours) elapses in as much as the frost accumulated on the evaporator of the refrigerator is evaporated at room temperature due to the long-time power cutoff of the mechanical refrigerator, the program is automatically reset or branched to start the compression mode or to produce an alarm sound or signal in accordance with the user's request. This operation can heighten the energy efficiency.

On the other hand, if the operation time of the defrost heater exceeds a preset time (e.g., one to 120 minutes) in a state that the defrost temperature switch for controlling the operation time of the defrost heater malfunctions, the program is automatically reset to cut off the power supply to the defrost heater and to produce a compression mode output signal or an alarm signal in accordance with the user's request.

It is preferable to automatically reset the defrost time or the defrost heater operation time in accordance with the user's request because the characteristics of evaporators in respective mechanical refrigerators may differ.

In order to control the compression mode and the defrost mode, the control unit 110 may use the input times (e.g., compression/defrost operation period and defrost pause time) or may compare times, which can be detected by sensors installed to sense the states (e.g., temperature, pressure, and humidity) in the compression mode or the defrost mode, with reference values stored through experiments.

The input unit 120 may be a battery or a capacitor for applying its power to the electronic defrost timer 100. Specifically, the input unit 120 is an emergency power supply that is used to prevent the accumulated time from being erased by up/down-counting the input time, and to temporarily store the accumulated time in the memory (not illustrated), in order to control the compression mode and the defrost mode when the power supply to the electronic defrost timer 100 is cut off due to the cutoff of the refrigerator AC power supply or the turn-off of the thermostat 20.

That is, if the power supply to the electronic defrost timer is cut off due to the cutoff of the refrigerator AC power supply or the turn-off of the thermostat 20 while the refrigerator operates in the compression mode or the defrost mode, the input unit stores the compression/defrost operation time accumulated till then in the memory (not illustrated) of the control unit. Thereafter, if the power is normally applied to the electronic defrost timer, the control unit 110 re-operates in the compression mode or the defrost mode by using the accumulated time stored in the memory (not illustrated).

If the input time, i.e., the compression/defrost operation period and defrost pause time, has arrived in a state that the control unit 110 continuously accumulates the time by up/down-counting the compression/defrost operation time in the compression mode or the defrost mode, the control unit 120 provides an output signal for directly controlling the compression mode or the defrost mode to the output unit 130, and the output unit 130 serves to control the compression mode or the defrost mode by using the output signal.

FIG. 4 is a block diagram illustrating the construction of program modules installed in the electronic defrost timer for a mechanical refrigerator according to the present invention. Referring to FIG. 4, the program modules provided in the control unit will now be described in detail.

The program installed in the control unit includes a control module 111, a compression control module 112, and a defrost control module 113.

The control module 111 receives an input of the compression/defrost operation time in the compression mode or the defrost mode in accordance with a user's request, accumulates the input operation time by up/down-counting the input operation time, and transmits the output signal for controlling the compression mode or the defrost mode to the compression control module 112 or the defrost control module 113.

The compression control module 112 serves to operate the compressor by applying the power to the compressor using the output signal of the control module 111.

The defrost control module 113 serves to operate the defroster by applying the power to the defroster using the output signal of the control module 111.

In particular, the control module 111 can perform a timer routine for checking the system to match a specified time inputted according to the user's request.

That is, if the timer routine is set to check the system by inputting the specified time, the control unit 110 checks at any time the system state of the mechanical refrigerator within the specified time during the operation of the mechanical refrigerator. It is preferable that the specified time is set to 0.01 to one second.

If the power supply to the defrost timer is cut off due to the cutoff of the refrigerator AC power supply or the turn-off of the thermostat 20 during the checking of the system state of the mechanical refrigerator, the control unit stores the accumulated time in the memory (not illustrated) for controlling the compression mode or the defrost mode, while if the power is re-applied to the electronic defrost timer, the control unit controls the compression mode or the defrost mode again using the accumulated time stored in the memory (not illustrated).

Hereinafter, the operation of the electronic defrost timer as constructed above according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 5 is a flowchart explaining the operation principle of the electronic defrost timer for a mechanical refrigerator according to the present invention, and FIG. 6 is a flowchart explaining a timer routine for checking the system of the electronic defrost timer for a mechanical refrigerator according to the present invention.

Before the electronic defrost timer is shipped from its manufacturing factory, a compression/defrost operation period and a defrost pause time are inputted to the electronic defrost timer (S504), following the initialization process of the electronic defrost timer (S502).

It is apparent that the compression/defrost operation period and the defrost pause time can also be changed after the shipping of the electronic defrost timer.

The control unit 110 counts the input compression/defrost operation period and the defrost pause time, and operates the compressor by executing the compression control module 112 in accordance with the counted compression/defrost operation period and the defrost pause time (S506).

The control unit 110 may first operate the defroster by executing the defrost control module 113.

If the compression operation time that is down-counted by the control unit 110 becomes “0” or the compression operation time that is up-counted by the control unit 110 becomes a predetermined value while the refrigerator operates in the compression mode (S508), the control unit 110 stops the compressor and operates the defroster by executing the defrost control module 113 (S510).

In the same manner, if the defrost operation time (including the defrost pause time) that is down-counted by the control unit 110 becomes “0” or the defrost operation time (including the defrost pause time) that is up-counted by the control unit 110 becomes a predetermined value while the refrigerator operates in the defrost mode (S512), the control unit 110 stops the defroster and operates the compressor by executing the compression control module 113 (S506).

On the other hand, in accordance with the user's request, a timer routine for the system checking may be executed for a specified time in the range of 0.01 to one second, while the refrigerator operates in the compression mode or the defrost mode (S602). At a specified time point initially set, the control unit 110 confirms the on/off state of the power supply to the electronic defrost timer (S604).

If the AC power supply to the electronic defrost timer is in an off state, the control unit 110 checks the system of the electronic defrost timer (S606), and stores the compression/defrost operation time accumulated in the compression mode or the defrost mode in the memory of the control unit (S608). By contrast, if the AC power supply to the electronic defrost timer is in an on state, the control unit 110 checks the system of the electronic defrost timer (S610), checks whether a compression/defrost mode switch is in an on (S612). If the switch is in an on state, the control unit checks whether the present mode is the compression mode (S614), while if the switch is in an off state, the control unit terminates the timer routine. If the present mode is the compression mode at step S614, the control unit switches the present mode over to the defrost mode (S616), while if the present mode is the defrost mode at step S614, the control unit switches the present mode over to the compression mode (S618).

In the embodiment of the present invention, the compression mode or the defrost mode is controlled using the input time, i.e., the compression/defrost operation period and the defrost pause time. However, it is apparent that the compression mode or the defrost mode can also be controlled by sensing the states (temperature, pressure, humidity, and so forth) in the compression mode or the defrost mode and comparing the sensed values with reference values determined by experiments.

As described above, according to the electronic defrost timer for a mechanical refrigerator according to the present invention, since the input unit, the control unit, and the output unit are mounted on the PCB and the compression mode or the defrost mode is controlled by the program, the compression/defrost operation time of the refrigerator can be promptly controlled without any modification of moldings, and thus the manufacturing cost and time can be saved.

In addition, the accumulated time for controlling the compression mode or the defrost mode is stored so as to prevent the accumulated time from being erased even if the power supply to the electronic defrost timer is cut off, and thus the refrigerator can normally be re-operated in the compression mode or the defrost mode in accordance with the stored accumulated time.

In addition, since the electronic defrost timer has a structure operating on the same wiring and mounting conditions as those of the existing mechanical defrost timer for the mechanical defrost timer, it can be used without any modification of the wiring and mounting conditions, and thus the manufacturing cost and time can be saved.

Although preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. An electronic defrost timer for a mechanical refrigerator, comprising: an input unit applying its power to the defrost timer and receiving an input of time for controlling the defrost timer; a control unit controlling a compression mode or a defrost mode by using the input time and a program; and an output unit directly controlling the compression mode or the defrost mode under the control of the control unit.
 2. The electronic defrost timer of claim 1, wherein the control unit controls the compression mode or the defrost mode by using either of the input time and a sensor sensing the state in the compression mode or the defrost mode.
 3. The electronic defrost timer of claim 1, wherein the control unit comprises a memory automatically storing an accumulated time when the mechanical refrigerator is operated or when the power supply is cut off.
 4. The electronic defrost timer of claim 1, wherein the program of the control unit comprises: a control module controlling the compression mode and the defrost mode by counting a compression/defrost operation time and a defrost pause time inputted from the input unit; a compression control module operating the compression mode under the control of the control module; and a defrost control module operating the defrost mode under the control of the control module.
 5. The electronic defrost timer of claim 4, wherein the control module of the control unit executes a timer routine for checking a system to match the time inputted by a user, stores the accumulated time in a memory if the power supply to the mechanical refrigerator is cut off, and re-operates the compression mode or the defrost mode by using the accumulated time stored in the memory if the power is applied to the mechanical refrigerator.
 6. An electronic defrost timer for a mechanical refrigerator, comprising: an input unit receiving an input of time for controlling the defrost timer; a control unit controlling a compression mode and a defrost mode by using the input time and a program; and an output unit directly controlling the compression mode or the defrost mode under the control of the control unit.
 7. The electronic defrost timer of claim 6, wherein the control unit comprises a memory storing an accumulated time irrespective of the on/off state of an input power.
 8. The electronic defrost timer of claim 1, wherein the program is automatically reset or branched when a predetermined time elapses in as much as frost accumulated on an evaporator of the refrigerator is evaporated at room temperature due to a long-time power cutoff of the mechanical refrigerator.
 9. The electronic defrost timer of claim 1, wherein if an operation time of a defrost heater exceeds a preset time in a state that a defrost temperature switch controlling the operation time of the defrost heater malfunctions, the program is automatically reset to cut off the power supply to the defrost heater and to produce a compression mode output signal or a signal in accordance with a user's request.
 10. The electronic defrost timer of claim 6, wherein the program is automatically reset or branched when a predetermined time elapses in as much as frost accumulated on an evaporator of the refrigerator is evaporated at room temperature due to a long-time power cutoff of the mechanical refrigerator.
 11. The electronic defrost timer of claim 6, wherein if an operation time of a defrost heater exceeds a preset time in a state that a defrost temperature switch controlling the operation time of the defrost heater malfunctions, the program is automatically reset to cut off the power supply to the defrost heater and to produce a compression mode output signal or a signal in accordance with a user's request. 